When transporting items, conventional methods generally include the use of either an open trailer or a solid enclosed trailer. Open trailers have the disadvantage of leaving the carried items open to line of sight, precipitation, and sun damage. Enclosed trailers can be significantly more expensive and also have the disadvantage of extra weight provided by the solid structure.
Other trailer covers have been proposed. For example, U.S. Pat. No. 6,092,856 discloses a canopy style trailer cover including a plurality of U-shaped frame members, each having a pair of opposing arms that terminate at a distal end. The respective ends are pivotally joined to the side of a trailer. A cover member having a substantially semi-circular cross-sectional configuration is mounted over the frame members. The cover can be pivoted and collapsed toward the rear of the trailer in an accordion style fashion.
U.S. Pat. No. 7,374,225 discloses a tarpaulin system including a plurality of inverted U-shaped support bows extending laterally across a trailer and secured to sections of the tarpaulin. Each support bow has rollers secured thereto for sliding movement along rails on each side of the trailer. A plurality of pairs of inverted U-shaped uplifting bows also extend laterally across the trailer and are pivotally secured to the support bows on opposite sides to spread apart during opening of the system. Intermediate support rods are secured between adjacent pairs of uplifting bows and extend laterally across the trailer between the uplifting bows beneath the tarpaulin sections to restrict the tarpaulin sections from falling between the uplifting bows when the system is closed.
However, these and other known trailer covers suffer from one or more disadvantages. These disadvantages include difficulty in installing and removing the cover or tarpaulin, insecurely affixed cover or tarpaulin, costly manufacturing, or insufficiently enclosing the area above the transported items. Thus, there remains a need in the art for an improved retractable canopy assembly for protecting transported items.